International Monetary Fund head Christine Lagarde has been placed under investigation by French magistrates for her alleged role in a long-running fraud case involving the former owner of Adidas. She has described the investigation as "totally unfounded" and plans to appeal the decision.

Lagarde is being investigated, the New York Times reports, for alleged negligence in her role as an "assisted witness" in a 2008 arbitration between the French government and Bernard Tapie, a former French cabinet minister and onetime owner of Adidas sportswear. Tapie was awarded 403 million euros ($531 million) in a settlement with the late, state-operated Credit Lyonnais. At the time, Lagarde was finance minister for former French President Nicolas Sarkozy. Lagarde was interviewed for a fourth time this week about her role in the case.

If she is found negligent, Lagard faces a 15,000 euros ($19,800) fine and up to one year in prison. But as the Times points out, that while an investigation is usually only launched with enough evidence to eventually bring charges and go to trial, "the reality is that many such investigations drag on for years with no charges being filed before being dropped."